An independent, hardware-specific derivative of Markus Reschke's Component Tester firmware. This build integrates an Arduino Nano, a 1.77-inch ST7735S display, a rotary encoder, a modified 15–45 V Zener-test converter, and an external transistor-based LC oscillator.
Original Component Tester firmware: Markus Reschke.
This hardware adaptation, LC-meter integration, PCB work, photographs, and project documentation: Aleksei / Aleksei327 / 995uet.
This repository is an unofficial derivative branch, not the official upstream project. See CREDITS.md for the complete project lineage.
Caution
The automatically generated Gerber archive is not production-ready.
- Markus Reschke Component Tester firmware version 1.49m.
- Arduino Nano form factor and 16 MHz clock.
- 1.77-inch, 128×160 ST7735S TFT.
- Rotary encoder interface.
- 15 V input supply.
- Modified DC/DC converter for Zener-diode testing, approximately 15–45 V.
- External LC meter built around bipolar transistors rather than the original LM311 approach.
- Reference-capacitor relay controlled by an active-high +5 V signal.
- Prebuilt firmware both with and without the external LC meter.
- EasyEDA schematic and PCB source exports, PDF drawings, BOM, photographs, and archived experimental LC-meter revisions.
The assembly description calls the Nano MCU an ATmega328PB, but the included source Makefile is configured for an ATmega328P:
MCU = atmega328
PARTNO = m328p
FREQ = 16Check the actual marking on your microcontroller before compiling, flashing, or changing fuses. The supplied prebuilt binaries are documented as the files used by this project, but their target signature cannot be proven from an Intel HEX file alone.
The LC-enabled firmware differs from the non-LC build in only three source files:
config.hconfig_328.htools_LC_Meter.c
The LC build enables the basic frequency counter and LC-meter menu, changes the reference capacitor to active-high control, adds a 140 Hz zero-offset correction, and disables several optional features to fit the ATmega328 flash. See docs/FIRMWARE.md for the exact functional differences.
The Nano hardware also requires modifications:
- program through the ISP/SPI header with a programmer such as USBasp;
- remove the capacitor connected to MCU pin 20 as shown in the project schematic;
- disconnect the Nano
LLED, or its series resistor, from MCU pin 17; - keep D4 / PD4 / T0 free from the display and connect it to the LC oscillator frequency output.
See docs/HARDWARE.md before assembling or modifying a Nano.
Ready-to-flash files:
Both Flash (.hex) and EEPROM (.eep) files are required for a fresh installation. Back up the current Flash, EEPROM, and fuse values before writing anything. The hardware author confirms the working fuse set as LF=F7, HF=D9, EF=FD. Detailed commands and the stale generic EF=FC value found in the archived Makefile are documented in docs/FLASHING.md.
The source trees are preserved separately:
The source was audited and compared, but it was not rebuilt in this workspace because AVR-GCC, GNU Make, and AVRDUDE were not installed. A later build artifact found in the source archive is not byte-identical to the named public LC firmware, so the public prebuilt firmware is preserved separately and identified by SHA-256.
- EasyEDA schematic and PCB exports
- main tester PDF drawings
- recommended transistor LC meter V1
- experimental LC-meter V2/V3 archive
- bill of materials
- unverified Gerber archive
The transistor V1 LC meter is the primary design in this repository. The project author reported it as more stable than V2 and V3; those op-amp versions are retained only for reference.
The EasyEDA PCB image and PDF copper artwork are build-proven by the hardware author. The separate generated Gerber ZIP remains quarantined because its automatic connectivity/DRC report is not clean.
docs/ project, hardware, firmware, and flashing notes
firmware/prebuilt/ canonical public HEX and EEPROM images
firmware/source/ clean LC and non-LC source trees
hardware/ EasyEDA exports, PDFs, BOM, and Gerber warning
media/photos/ original construction photographs
media/video-stills/ YouTube thumbnails
The 435 MB demonstration video and raw download archives are kept in the local acquisition folder but are intentionally excluded from Git. GitHub blocks regular repository objects larger than 100 MiB; the original Google Drive and YouTube links remain in docs/SOURCES.md.
- Test only disconnected, unsoldered components unless you fully understand the circuit involved.
- Fully discharge capacitors before connecting them.
- Never connect the test probes to mains or to an energized circuit.
- The Zener-test section generates hazardous voltages relative to low-voltage logic. The original notes limit the external source to 50 V.
- Incorrect fuse settings can make the MCU inaccessible to a normal ISP programmer. Preserve known-working fuse values unless you have verified the exact MCU and clock circuit.
- Hardware and wiring
- Firmware variants and modifications
- Build and flashing guide
- Local vs. Google Drive inventory
- Original sources and videos
- Credits and project lineage
- Licensing notes
- Transistortester Warehouse
- Markus firmware source tree
- Mikrocontroller.net Markus mirror
- This hardware project on OSHWLab
- Project files on Google Drive
The firmware source is distributed under EUPL v1.2 in the supplied archive. Hardware, media, and documentation provenance is described in LICENSES.md.